The Collaborative International Dictionary of English v.0.48:

Vexation \Vex*a"tion\, n. [L. vexatio: cf. F. vexation.]
   1. The act of vexing, or the state of being vexed; agitation;
      disquiet; trouble; irritation.
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            Passions too violent . . . afford us nothing but
            vexation and pain.                    --Sir W.
                                                  Temple.
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            Those who saw him after a defeat looked in vain for
            any trace of vexation.                --Macaulay.
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   2. The cause of trouble or disquiet; affliction.
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            Your children were vexation to your youth. --Shak.
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   3. A harassing by process of law; a vexing or troubling, as
      by a malicious suit. --Bacon.
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   Syn: Chagrin; agitation; mortification; uneasiness; trouble;
        grief; sorrow; distress. See Chagrin.
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WordNet (r) 3.0 (2006):

vexation
    n 1: anger produced by some annoying irritation [syn:
         annoyance, chafe, vexation]
    2: the psychological state of being irritated or annoyed [syn:
       irritation, annoyance, vexation, botheration]
    3: something or someone that causes anxiety; a source of
       unhappiness; "New York traffic is a constant concern"; "it's
       a major worry" [syn: concern, worry, headache,
       vexation]
    4: the act of troubling or annoying someone [syn: annoyance,
       annoying, irritation, vexation]